Production of Highly Metalized Direct Reduced Iron (DRI) in Fluidized Bed by CO and H₂: Determination of the Kinetic Triplet

In this study, calcined iron ore samples from Mente & scedil;, T & uuml;rkiye were isothermally reduced in a laboratory-scale fluidized bed reactor using several blends of CO, H2, and N2 gases. The experiments were carried out at 3 temperatures (800 degrees C, 850 degrees C, and 900 degrees C), with 4 reductant concentrations (1:1:2, 0:1:3, 1:1:6, and 1:0:3 molar ratios for "CO:H2:N2," respectively). Almost full metallization was achieved with the first gas composition at 800 degrees C and 850 degrees C. However, 900 degrees C tests exhibited the lowest reduction degrees for almost all reductant compositions due to the sintering of the particle surfaces. The results showed that the conversion of the ore was more sensitive to reductant concentration (especially to the H2 ratio in the mixture) than the temperature. The kinetic analysis revealed that the gaseous reduction of calcined Mente & scedil; iron ore in the fluidized bed can be represented by the "Two-Dimensional Diffusion, D2(alpha)" model and the process requires 19.73 kJ/mol activation energy (Ea). Thanks to the low Ea requirement and relatively high Fe2O3 content, calcined Mente & scedil; iron ore was evaluated as a proper raw material for DR applications.